1. Field of the Invention
The present invention relates to radio communication systems, particularly a radio communication system that carries out transmission and reception of multicarrier signals, a transmission terminal, and a reception terminal.
2. Description of the Background Art
In the field of radio communication systems, various studies have conventionally been made about the reliability of transmitted and received data.
For example, Japanese Patent Laying-Open No. 2004-088268 discloses, in order to improve the error rate of reception data with respect to signals that are transmitted again (retransmission signal) from the sender side when transfer error is detected at the receiver side in an OFDM (Orthogonal Frequency-Division Multiplexing)-CDMA (Code Division Multiple Access) communication scheme, the technique of increasing the number of spread codes to be allocated to retransmission signals as the retransmission count increases.
With the widespread use of various portable communication devices including cellular phones, it is now increasingly critical to improve the reliability of data transmitted and received in a radio communication system.